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Effects of Er2O3 on Electrical Properties of the SnO2.CoO.Ta2O5 Varistor System |
| WANG Chun-Ming;WANG Jin-Feng;CHEN Hong-Cun;SU Wen-Bin;ZANG Guo-Zhong;QI Peng |
| School of Physics and Microelectronics, National Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 |
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| Cite this article: |
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WANG Chun-Ming, WANG Jin-Feng, CHEN Hong-Cun et al 2004 Chin. Phys. Lett. 21 716-719 |
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Abstract We investigate the effects of Er2O3 on electrical properties of the SnO2.CoO.Ta2O5 varistor system sintered at 1400°C. It is found that all the samples have excellent nonlinear electrical characteristics and the sample with 0.50 mol% Er2O3 has the best nonlinear electrical property and the highest nonlinear coefficient (α = 43.7). The high nonlinear coefficient value obtained in the system indicates that the SnO2-based varistor is a candidate for ZnO-based varistors in commercial applications. Er2O3 additive can significantly affect the average grain size. With increasing Er2O3 concentration from 0.10 mol% to 1.00 mol%, the average grain size decreases from 21.2μm to 10.6μm, the breakdown electrical field increases from 208 V/mm to 459 V/mm, and the relative electrical permittivity decreases from 2440 to 1210. The reason that the grain size decreases with increasing Er2O3 concentration is explained. Also, we present a modified defect barrier model to illustrate the grain-boundary barrier formation of Er2O3-doped SnO2 based varistors.
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| Keywords:
73.30.+y
72.20.Ht
77.22.Ch
84.32.Ff
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Published: 01 April 2004
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| PACS: |
73.30.+y
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(Surface double layers, Schottky barriers, and work functions)
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72.20.Ht
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(High-field and nonlinear effects)
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77.22.Ch
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(Permittivity (dielectric function))
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84.32.Ff
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(Conductors, resistors (including thermistors, varistors, and photoresistors))
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